"A man who aspires to the high post should have patience and not be excitable," Nitish said at the Janata Dal (United) convention in Rajgir on Tuesday and went on to give a point-by-point rebuttal of Narendra Modi's attack on him at the BJP’s rally in Patna on Sunday.

"His Red Fort dreams will remain dreams," Nitish said.

Modi had urged people to “uproot and punish” the backstabbers, a reference to the acrimonious split between the BJP and the JD(U).

“This is not how democracy works. This is the language of Hitler, of a person who brooks no opposition,” Nitish said

Warning fascism and not merely communalism was the biggest challenge before the country, the JD(U) leader took a dig at the name of BJP's mega rally, hunkar (battle cry).

“It reflects arrogance. These are fascist traits. Hitler's associate Goebbels had said if you repeat a lie hundred times, it appears to be the truth. This is what they do."

He took pot-shots at the BJP's “propensity to invoke Hindu gods for political goals”.

"First they had Lord Rama as their active player. Now they have involved Lord Krishna in caste politics by appealing in his name to a specific community (Yadavs),” Nitish said.

“Lord Krishna went from Mathura to Dwarka, which was a port city. You speak of Ram Manohar Lohia. He has said Ram united north with south while Krishna united east with west. Here people take names to divide castes," he added.

Modi had told the gathering that he had come from Dwarka to “take responsibility of the wellbeing of the descendants of Shri Krishna (Yadavs)”.

Nitish also punched holes in "historic claims" made by the Gujarat chief minister in his speech. "The man (Modi) has an amazing grasp of history. He should know Chandragupta was of Maurya dynasty, not of Gupta dynasty. Neither is Takshashila in Bihar, as Modi said, it is situated in Pakistan." Nitish said Modi may believe that Alexander was defeated by Biharis but history says the Greek emperor never reached Bihar.

The Bihar chief minister said Modi's statements were a figment of his imagination. "We were not seated at the same table at any lunch hosted by PM Manmohan Singh. That tale is a lie just as the party saying that wind's blowing in Modi's favour," he said.

Nitish was referring to Modi's statement that the Bihar chief minister was a hypocrite for refusing to eat while sitting on the same table with him because he was possibly afraid of being photographed.

Video: Nitish mocks BJP's knowledge of history

The JD(U) leader also slammed Modi for saying he had abandoned Loknayak Jayaprakash Narayan, popularly known as JP. "Who left JP? Why was it said? Just for rhyming JP and BJP."

Responding to Modi’s statement that he understood poverty better because he sold tea on a railway platform, Nitish said, “I have no experience of selling tea but I also belong to a backward community. But being a backward alone is not enough for becoming the PM," he said.

"Great leaders like Lohia, JP, Raj Narayan and VP Singh belonged to upper castes, but they fought for the uplift of the backward castes," he said.

On Sunday, referring to Nitish, Modi had said, "People in Bihar are not opportunistic, except a few."

"If the BJP was so hurt, why did the party fight 2010 elections in alliance with the JD(U)? Because they could not do without our party. So, tell me, who is opportunistic? It was the BJP that betrayed us and weakened the anti-Congress forces."

Nitish was instrumental in getting the JD(U) to sever a 17-year-old alliance with the BJP in June following Modi's elevation - first as the saffron party's campaign committee chief for the 2014 Lok Sabha elections and then as its PM face.